Letter to the Editor

The environmental imprint on molecular layering in the dusty streamer of M512

¹ European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85478 Garching bei München, Germany
² European Southern Observatory, Alonso de Córdova 3107, Vitacura, Region Metropolitana de Santiago, Chile
³ SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK
⁴ INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy
⁵ Department of Astronomy, University of Virginia, Charlottesville, VA 22904, USA
⁶ Department of Astronomy, University of Florida, Gainesville, FL 32611, USA
⁷ Earth and Planets Laboratory, Carnegie Institution for Science, 5241 Broad Branch Road, NW, Washington, DC 20015, USA
⁸ Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215, USA

^★ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 27 February 2026
Accepted: 13 April 2026

Abstract

Protostellar streamers are elongated structures that channel material from larger scale onto disks, influencing their physical and chemical evolution. The M512 protostar in Orion/Lynds 1641 hosts one of the most massive and extended streamer discovered so far, offering a unique opportunity to study these processes. We investigated the morphology, chemistry, and origin of this streamer, along with its potential impact on the protostellar disk. Using archival ALMA observations of C¹⁸O, DCO⁺, N₂D⁺, and HCO⁺, we compared their spatial distributions through moment maps and spatial profiles. The streamer shows clear chemical stratification: C¹⁸O lies on the western side of the protostar, N₂D⁺ is farther out to the east, and DCO⁺ is in the middle. This suggests that the structure has been shaped by environmental effects, rather than tracing a single coherent infalling flow, with only the densest gas near the protostar likely to accrete onto the disk. Overall, the bulk of the streamer reflects the physical and chemical imprint of the surrounding cloud, highlighting the importance of environmental shaping in interpreting streamer–disk connections and their role in disk growth.